The blade roots are inserted into the disk groove via a window formed in said groove, and they are held radially and axially relative to the axis of the turbomachine by having co-operating shapes, the groove having a cross-section that is of dovetail-shape, or the like, for example.
In order to prevent the blade roots from sliding freely in the groove of the disk and escaping therefrom through the above-mentioned window, a locking member is inserted through said window into the groove in the disk for the purpose of being displaced within the groove by sliding until it reaches a retaining notch formed in the groove.
Document FR-A-2 810 366 discloses locking members each comprising a radial screw with a head disposed between two blade roots and bearing against the bottom of the groove. Tightening the screw enables the locking member to be displaced radially outwards and enables it to be held in place in the above-mentioned notch in the groove so as to lock the blades in the groove in the disk.
The blade roots are generally mounted with a certain amount of clearance in the peripheral groove of the disk. When the turbomachine is in operation, the blades are subjected to high levels of centrifugal force and to vibration that can lead to the screws of the locking member loosening or jamming.
One solution to that problem consists in deforming the portion of the locking member that receives the screw so as to prevent it from turning. Nevertheless, such deformation by compression is difficult or impossible to achieve when the pitch between the blades is small and hinders or prevents a compression tool being put into place.
It has also been found that such jamming of the screws makes it impossible to disassemble the locking members, thereby making it necessary to destroy them with a drill, and that runs the risk of damaging the rotor disk.
Documents FR-A-2 616 480 and FR-A-1 541 373 also disclose devices for locking the roots of blades, which devices are elastically deformable U- or Ω-shaped parts with their openings directed towards the opening in the groove, and these members have their free ends moved towards each other by means of a suitable tool for the purpose of clamping these parts onto themselves and causing them to slide along the groove into predetermined locking positions. It is not always easy to get hold of the ends of these parts and to clamp them together by means of the tool so as to enable the parts to be slid along the groove into their locking zones, and as a general rule, it is even more difficult to move them in the opposite direction for the purpose of unlocking the blade roots and disassembling the blades.